As introduction to Elisava‘s Advanced Design & Digital Architecture Masters (ADDA), students where asked to work up with an interesting building and describe why they found it interesting. Oriol Carrasco developed a Case Study on the Frei Otto Mannheim Multihalle, constructed in Mannheim (Germany) in 1975, for be part of the RuralCity exhibition held in Mannheim the same year.
One of the most important facts about the Multihalle (and the reason why Oriol chose it) is the generation process of the pavilion, based on a Gridshell.
Otto developed a Gridshell form finding process that involved hundreds of scale models of Gridshells. He developed a catalog with several forms and shapes that the Gridshells can generate when hanged. Just like Gaudi, Otto worked on scale models to see the behavior of the grid he was working on. The studies he did where about form and shape but also involved architectural basic needs, as space and light.
The Gridshell is a structure which derives its strength from a double curvature surface. The most important thing about this kind of membranes is the perimeter, which has to be rigid enough to support the deadweight of the structure and most important, all the loads sitting above it. Otto worked on models with a rigid permiter from which to hang the Gridshells he fabricated. After that he hanged on the Gridshell small loads that would represent actual and real weight of the materials used to build the structure and the membrane.
When the form findig process was over, and Otto just had in mind what he wanted to build, the construction process begun. Take in mind that in that time computers where not as accessible as they are now, so all the calculations where done by hand.
The Gridshell was assembled on the ground and very carefully it was put it in place. Due its dimensions, this process was quite long and a lot of scaffolding was needed. The other important fact about its size was the stifness of the entire structure, Otto’s team designed it composed by hundreds of small triangular cells to give the whole structure the strenght needed. Obviously there were parts that needed and extra structural reinforcement.
The resulting building that Otto designed turn out to be an amazing construction, from the inner space to the smallest details of structure. Finally the building served as exhibition space and hosted the restaurant of the RuralCity exhibition.
If you want to know more about the Frei Otto Mannheim Multihalle, there is an IL (IL 13) that covers the entire work process, detailing technical aspects of the design and showing all construction phases.